Method for purifying and refining epsi caprolactam

A technology of caprolactam and refining method, which is applied to the preparation of lactam, separation/purification of lactam, chemical instruments and methods, etc., which can solve the problems of reduced reaction efficiency and lower absorption value of potassium permanganate

Active Publication Date: 2007-11-14
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Excessive hydrogenation will reduce the reaction efficienc

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] The gas-phase Beckmann rearrangement reaction of cyclohexanone oxime was carried out in an 80ml fixed-bed reaction device. The inner diameter of the reactor was 28mm, and the molecular sieve catalyst with a high silicon-aluminum ratio MFI structure was loaded with 9.45g (Φ1.8mm strip catalyst). Pressure 0.1MPa, catalyst bed reaction temperature 365°C-385°C, carrier gas flow rate 3.0L / gcat / hr, cyclohexanone oxime WHSV 2h -1 , The partial pressure range of the mixed material: cyclohexanone oxime 5.5kPa-11.6kPa, methanol (solvent) 36.9kPa-70.6kPa, nitrogen (carrier gas) 19.4kPa-52.6kPa,. The reaction product was collected by circulating and cooling the ethylene glycol solution at -5°C to obtain a reaction product containing ε-caprolactam.

[0036] First, the reaction mixture is distilled by simple distillation to remove methanol, low-boiling impurities and high-boiling impurities, and finally obtain crude ε-caprolactam. On the 6890 type gas chromatograph of Agilent Compan...

Embodiment 2

[0040] As described in Example 1, take 2.0Kg of the crude ε-caprolactam obtained by the above simple distillation method, put it into a 10L reactor, add 2.0Kg of n-chlorobutane, heat to 60-70°C, and stir for 30 minutes to make ε-caprolactam is completely dissolved in this solvent. Continue cooling while stirring, the temperature is cooled from 70°C to about 15°C, and ε-caprolactam crystals are completely precipitated. After centrifugal separation, 1.90Kg99.92%ε-caprolactam crystals and 2.10Kg95.8% n-chlorobutane were obtained. Chlorobutane solvent is recovered. 1.94Kg ε-caprolactam crystals were returned to the 10L reactor, 1.94Kg n-heptane was added, stirred and washed at room temperature for 30 minutes, and then centrifuged to obtain 99.95% ε-caprolactam crystals and 98.8% n-heptane (otherwise included 1.00% ε-caprolactam). n-heptane solvent for recovery. The PM value of the obtained ε-caprolactam was 129s, and the E value was <0.6.

[0041] Hydrogenation reaction: Take...

Embodiment 3

[0043] As described in Example 1, the ε-caprolactam crystal obtained by using n-chlorobutane as crystallization solvent and washing solvent was subjected to hydrogenation reaction, and the hydrogenation reaction was as follows.

[0044] Hydrogenation reaction: Take 99.97% ε-caprolactam crystals washed once with 1.9Kg of n-chlorobutane, add them to a 5L reaction kettle, add 190g SRNA-4 industrial grade amorphous nickel hydrogenation catalyst, and heat to 90°C Around, feed hydrogen, the flow rate of hydrogen is controlled at 0.6L / min, the reaction pressure is maintained at 5 atm, the ε-caprolactam in molten state is contacted with hydrogen, and reacted for 1 hour. Afterwards, the reaction product was distilled under reduced pressure at about 1 mmHg to obtain 1.86 Kg ε-caprolactam with a yield of 98%. The quality of the obtained ε-caprolactam product was analyzed, the PM value was 32000s, and the E value was <0.04.

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Abstract

This invention relates to a refine means of epsilon - caprolactam by separation and purification. The feature of the invention lay in that it includes the step of crystallize epsilon - caprolactam from ethereal solution containing crude epsilon - caprolactam.The product purity can reach 99.98%upwards, absorption value of potassium permanganate is greater than 10000 or more, the extinction value of epsilon - caprolactam at 290nm wavelength is 0.05 or smaller. The invention wholly meet the require of industrial product.

Description

technical field [0001] The present invention relates to a method for producing ε-caprolactam, more specifically, the present invention relates to a method for separating, purifying and refining ε-caprolactam. Background technique [0002] ε-caprolactam is one of the important raw materials for synthetic fibers and synthetic resins, mainly used in the manufacture of polyamide fibers (nylon 6), resins and films. At present, the industrial production method of caprolactam is to use oleum as a catalyst and solvent, and cyclohexanone oxime undergoes a liquid-phase Beckmann rearrangement reaction. This process has the disadvantages of corroding equipment, polluting the environment, and unsatisfactory economic benefits, and a large amount of ammonium sulfate is produced as a by-product. [0003] The gas-phase Beckmann rearrangement reaction of cyclohexanone oxime on solid acid catalyst is a new process to realize the sulfur-free ammonification of ε-caprolactam. It has no problems ...

Claims

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Application Information

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IPC IPC(8): C07D201/16C07D201/04
Inventor 程时标孙斌王恩泉杨克勇张树忠吴巍闵恩泽
Owner CHINA PETROLEUM & CHEM CORP
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